Deep in eastern Cambodia, near the Vietnam border, is a lush rural landscape that has been ravaged by war. The U.S. secretly bombed here during the Vietnam War, and later Vietnam invaded to put down the brutal Khmer Rouge regime and occupy Cambodia.

Peace has finally come, but this quiet area dotted with rice paddies and rural workers is today the scene of a different kind of war: one to stop the spread of tuberculosis. TB is a deadly but curable disease that has taken hold in places like Cambodia, and throughout the developing world. The bacterium breeds where people live in poverty and in cramped quarters.

On the frontlines of this war is a top researcher from Harvard who has dedicated her career to taking care of refugees and children in Cambodia. Anne Goldfeld is a professor at Harvard's Immune Disease Institute. She also co-directs the Global Health Committee, along with her Cambodian medical partner, Sok Thim, a survivor of the Pol Pot regime that killed an estimated two million Cambodians in the 1970s.

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Working in the province of Svay Rieng, and in the capital of Phnom Penh, the two doctors have teamed up to provide early detection and long-term treatment for a population ravaged by TB, a disease considered all but eliminated in the West.

At the small Svay Rieng hospital, three hours from Phnom Penh, Sok and Goldfeld examine several young children who exhibit possible symptoms of TB. They need to determine whether it is in fact, TB, and quickly.

"She could develop meningitis and it could turn into coma," said Goldfeld of one young girl. "It could turn into disseminated TB ' -- tuberculosis that spreads beyond the lungs -- ' (and) she could die."

For more than a century, there were precious few ways to make that critical diagnosis. The sputum --or spit -- test has been around for more than 100 years.

The disease, which was known as "consumption" because it attacked the lungs and left patients withered and wasted, spread like wildfire through crowded American cities. Highly contagious, it was spread by people coughing in unventilated spaces. While the disease largely disappeared as living conditions improved, TB is now storming back throughout the developing world, helped in part by conditions in the slums -- a perfect breeding ground for bacteria -- and, in Cambodia, medical infrastructure ravaged by decades of war. The disease tends to afflict the poor, the weak and those infected by HIV, whose immune systems cannot battle the infection.

No New Tuberculosis Drugs or Tests

To Goldfeld's frustration, even though TB kills nearly two million people every year, there have been no new drugs or reliable diagnostic tests in decades.

"This is an infectious disease that is curable, and we just have old drugs to deal with it," said Goldfeld, who has done landmark work treating the co-infection of HIV and TB, a common and deadly combination. As the body weakens from HIV, without proper medication, TB moves in with fatal results.

Goldfeld has studied the best course of treatment and to determine when drugs for the co-infection should be introduced, but she is frustrated the world has not paid more attention to this new TB epidemic.

"I think everyone needs to ask themselves the question of why some people do not have access to medicines to treat a curable disease," said Goldfeld. "It's basically that if you are poor, you do not have the same access to medicines as people who are rich or who live in resource-rich countries."

The lack of a good diagnostic tool is making this epidemic much worse. It can take weeks, or even months, to find out which kind of TB a patient has. To make matters worse, if patients are not treated, or treated improperly, or go off medications, they can develop what is known as multiple-drug resistant TB, or MDR, and exacerbate it. That takes up to two years to treat, with painful and expensive drugs.

The average untreated MDR TB patient infects 12 to 15 people in his or her lifetime; they in turn infect the same number. Hence, the epidemic. According to the World Health Organization, Asia has the highest number of reported cases of drug-resistant TB.

But now, there is a new tool in the fight against TB: the GeneXpert, manufactured in California. It can analyze the genetic makeup of a sputum sample and diagnose in two hours what usually takes up to two months. The GeneXpert was developed with input by the Pentagon after the anthrax scare in 2001.

It looks something like a coffee machine, but costs about $20,000. Goldfeld is lucky enough to have one in Phnom Penh, where she is conducting a study with several colleagues to see how well the GeneXpert can diagnose TB in children. Because they don't generate enough sputum necessary for a TB test, it is potentially more difficult to use the GeneXpert for children. Results of the study are not expected for several months.

Last week, the World Health Organization endorsed the use of GeneXpert to diagnose TB, which infects more than nine million people a year. At the same time, the manufacturer, Cepheid, said it would offer a 75 percent reduction in the price of GeneXperts for countries most affected by TB.

Also key to fighting the epidemic is early detection and treatment of people showing symptoms, using community- based approaches to deliver care, as Goldfeld and Sok Thim have done in Cambodia.

Goldfeld says there are ways to help treat TB that don't require an expensive, high tech machine. A $20 donation to the Cambodian Health Committee can pay for an entire course of non-MDR TB treatment, or for a health worker to deliver drugs for MDR at a patient's home on a daily basis for a month

Goldfeld is also in the early stages of expanding her TB and HIV work in Ethiopia, a country of 85 million, with tens of thousands of cases of TB and HIV-TB co-infection. In Africa, TB is one of the leading causes of death for people with HIV.

India: The Highest Burden TB Country

And then there is India, at the epicenter of the TB crisis -- a country with nearly a quarter of the world's cases, about two million every year. It is considered by the WHO to be the No. 1 high-burden country in the world. In Delhi, a sprawling city of 14 million, there is an additional problem.

Throughout the slums are charlatans, quack medical practitioners dispensing misdiagnosis and incomplete treatment. Often they are the best the residents can get. These storefront operations dot the crowded streets and neighborhoods of makeshift homes teeming with people. Often the medical practitioner's credentials are displayed on signs outside, but when confronted these lay practitioners admit they don't have the qualifications or knowledge to diagnosis or treat a complex disease like TB.

Responding to the lack of medical care for many of India's estimated 410 million poor, an organization called Operation ASHA has decided to take a novel approach. Run by a former Indian government minister, Sandeep Ahuja, and an OB-GYN physician, Shelly Batra, Operation ASHA (or Operation Hope in English) is bringing treatment to those who need it most. Working from a small office in Delhi, Operation ASHA workers fan out, paying off the quacks, then placing their own counselors in the storefront clinics to make sure patients take all their medications.

The parents of 12-year-old TB patient Golshan told ABC News correspondent Dan Harris that they gavetheir savings to a medical practitioner who misdiagnosed their daughter.

The clinics are located in convenient place such as local Hindu temples. And ASHA follows up. Every time a patient comes in for drugs -- about three times a week -- he or she has to press their fingerprints into the computer that reads out data about treatment. If a patient misses a dose, ASHA is alerted and they go find the patient to make sure they take the pills.

Success can be measured in human terms. Every time a patient like 12-year-old Golshan is cured, that's a big step toward choking off a largely but incredibly dangerous epidemic. Golshan had been misdiagnosed by a medical practitioner who called himself a doctor (CLICK HERE for video of Dan Harris confronting the practioner). Her parents, who get by doing menial work at Golshan's school, say they gave him their savings. He then ended up sending her to a public hospital, where she was ultimately diagnosed with TB. Now she is being treated at an ASHA clinic a short walk from the school.

Golshan is now just weeks away from finishing her treatment. She is looking forward to continuing school, living a long and healthy life, and doing what she loves best -- dancing to music from Bollywood.

Golshan is now being treated at an ASHA clinic a short walk from school.

The "Be the Change: Save a Life" initiative is supported in part by the Bill & Melinda Gates Foundation.